Switch Configuration Control for Wireless Charging Circuits

This application claims priority to U.S. Provisional Patent Application No. 63/653,055, entitled “SWITCH CONFIGURATION CONTROL FOR WIRELESS CHARGING CIRCUITS,” filed on May 29, 2024, the technical disclosure of which is hereby incorporated by reference in its entirety and for all purposes.

The present disclosure relates to systems and methods for wireless charging. More particularly, embodiments of the present disclosure relate to wireless charging systems and mechanisms for charging vehicles using wireless charging circuits.

Generally described, inductive charging and capacitive charging are types of wireless power transfer. Wireless power transfer can be referred to as wireless charging. Inductive charging uses electromagnetic induction to generate, or otherwise provide, electricity to devices without necessarily requiring physical electrical connectivity. Specifically, various devices can be placed near a charging station or inductive pad without being precisely aligned or making electrical contact, a physical dock, an electric plug, and the like. Such devices can include, but are not limited to, vehicles, manufacturing equipment, consumer electronics, medical devices, and the like.

The systems, methods and devices of this disclosure each have several innovative embodiments, no single one of which is solely responsible for all of the desirable attributes disclosed herein. Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below.

In some aspects, the techniques described herein relate to a method of wireless power transfer, the method including: energizing a first wireless charging pad, the first wireless charging pad including a switching circuit; repeatedly toggling the switching circuit between a first switch configuration and a second switch configuration, wherein switches of a first half bridge of the switching circuit change a state between the first switch configuration and the second switch configuration, and wherein switches of a second half bridge of the switching circuit remain in a same state for the first switch configuration and the second switch configuration; and causing wireless power transfer from the first wireless charging pad to a second wireless charging pad using a voltage generated from the repeatedly toggling.

In some aspects, the techniques described herein relate to a method, further including: detecting one or more conditions, wherein the repeatedly toggling is performed in response to detecting the one or more conditions.

In some aspects, the techniques described herein relate to a method, wherein the one or more conditions relate to at least one of a load interfaced with the switching circuit, a voltage of a battery pack of a vehicle that includes the second wireless charging pad, or a voltage of a power supply associated with the first wireless charging pad.

In some aspects, the techniques described herein relate to a method, wherein a vehicle includes the second wireless charging pad, and a voltage of a battery pack of the vehicle is in a range from 200 Volts to 1000 Volts.

In some aspects, the techniques described herein relate to a method, wherein there is an unbalanced duty cycle between the first switch configuration and the second switch configuration for the repeatedly toggling.

In some aspects, the techniques described herein relate to a method, wherein the repeatedly toggling the switching circuit between the first switch configuration and the second switch configuration results in a lower voltage swing across a resonant tank of the first wireless charging pad that is electrically connected to the switching circuit compared with toggling the switching circuit between a third switch configuration, the first switch configuration, and the second switch configuration.

In some aspects, the techniques described herein relate to a method, wherein the switching circuit includes an H bridge circuit.

In some aspects, the techniques described herein relate to a method of wireless power transfer, the method including: wirelessly receiving power from a ground pad at a vehicle pad of a vehicle, the vehicle pad including a switching circuit; and repeatedly toggling the switching circuit between a first switch configuration and a second switch configuration, wherein switches of a first half bridge of the switching circuit change a state between the first switch configuration and the second switch configuration, and wherein switches of a second half bridge of the switching circuit are in a same state for both the first switch configuration and the second switch configuration.

In some aspects, the techniques described herein relate to a method, further including: detecting one or more conditions, wherein the repeatedly toggling is performed in response to detecting the one or more conditions.

In some aspects, the techniques described herein relate to a method, wherein the one or more conditions relate to at least one of a load interfaced with the switching circuit, a voltage range of a battery pack of the vehicle, or a voltage range of a power supply associated with the ground pad.

In some aspects, the techniques described herein relate to a method, wherein a voltage range of a battery pack of the vehicle is in a range from 200 Volts to 1000 Volts.

In some aspects, the techniques described herein relate to a method, wherein there is an unbalanced duty cycle between the first switch configuration and the second switch configuration for the repeatedly toggling.

In some aspects, the techniques described herein relate to a method, wherein the repeatedly toggling the switching circuit between the first switch configuration and the second switch configuration results in a lower voltage swing across a resonant tank of the vehicle pad that is electrically connected to the switching circuit compared with toggling the switching circuit between a third switch configuration, the first switch configuration, and the second switch configuration.

In some aspects, the techniques described herein relate to a method, further including charging a battery pack of the vehicle based on the power wirelessly received from the ground pad.

In some aspects, the techniques described herein relate to a wireless charging pad including: a switching circuit including a first half bridge and a second half bridge; a resonant tank electrically connected to the switching circuit, the resonant tank including a coil arranged for wireless power transfer; and a switch control circuit configured to repeatedly toggle the switching circuit between a first switch configuration and a second switch configuration, wherein the first half bridge changes a state between the first switch configuration and the second switch configuration, and wherein the second half bridge is in a same state in both the first switch configuration and the second switch configuration, wherein the wireless charging pad is configured to transfer sufficient wireless power for charging a battery pack with an operating voltage of at least 350 Volts.

In some aspects, the techniques described herein relate to a wireless charging pad, wherein the switch control circuit is further configured to detect one or more conditions, and wherein the switch control circuit configured to repeatedly toggle the switching circuit between the first switch configuration and the second switch configuration in response to detecting the one or more conditions.

In some aspects, the techniques described herein relate to a wireless charging pad, wherein the one or more conditions relate to at least one of a load interfaced with the switching circuit, a voltage range of a battery pack of a vehicle, or a voltage range of a power supply associated with the wireless charging pad.

In some aspects, the techniques described herein relate to a wireless charging pad, wherein the wireless charging pad is a ground pad.

In some aspects, the techniques described herein relate to a wireless charging pad, wherein the repeatedly toggling the switching circuit between the first switch configuration and the second switch configuration results in a lower voltage swing across the resonant tank compared with toggling the switching circuit between a third switch configuration, the first switch configuration, and the second switch configuration.

In some aspects, the techniques described herein relate to a wireless charging pad, wherein the switching circuit includes an H bridge circuit.

The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings where like reference numerals and/or terms can indicate identical or functionally similar elements. It will be understood that elements illustrated in the figures are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a drawing and/or a subset of the elements illustrated in a drawing. Further, some embodiments can incorporate any suitable combination of features from two or more drawings. The headings are provided for convenience only and do not impact the scope or meaning of the claims.

Generally described, one or more aspects of the present disclosure relate to systems and methods for wirelessly charging battery packs, which can have a relatively wide range of battery voltages. Illustratively, aspects of the present disclosure relate to wireless charging circuits that can operate under different input and output voltages through controlling switches of power electronics. In some embodiments, rather than periodically toggling (e.g., switching from open to closed, or switching from closed to open) each switch of a H bridge circuit in a wirelessly charging pad for a vehicle, a switch control circuit may control some switches of the H bridge circuit to toggle and control other switches of the H bridge circuit to not toggle when transitioning between states of the H bridge for wirelessly charging the vehicle. As such, a switch of the H bridge circuit may stay closed, a switch of the H bridge circuit may stay open, and some switches of the H bridge circuit may switch between closed and open states when transitioned between states of the H bridge for wirelessly transmitting and/or receiving power. For instance, the H bridge can repeatedly toggle between two switch configurations where one half bridge of the H bridge remains in a same state for the two switch configurations and the other half bridge of the H bridge changes states between the two switch configurations.

Advantageously, repeatedly toggling between particular switch configurations of a H bridge circuit controlled by the switch control circuit may result in a lower voltage swing across a resonant tank of a wireless charging pad (e.g., a ground pad and/or a vehicle pad), thereby allowing the wireless charging pad to charge battery packs under a relatively wide voltage range (e.g., from 200 V to 800 V or from 200 V to 1000 V). Additionally, fewer switching events associated with toggling between the particular switch configurations controlled by the switch control circuit may result in less energy loss.

Wireless charging devices are usable to wirelessly charge a vehicle, such as an electric vehicle with a battery pack. A wireless charging device (e.g., a ground pad or a vehicle pad) may cause power received from an external source, such as the grid, solar cell(s), and so on, to be wirelessly transmitted (e.g., via induction) to the electric vehicle. A ground pad may be positioned under a vehicle pad of an electric vehicle to charge the electric vehicle. A wireless charging direct current (DC)/DC converter (also referred to as aggregated DC/DC power converter) can include a DC/alternating current (AC) inverter in the ground pad, and an AC/DC rectifier in the vehicle pad. Power can be transmitted wirelessly from the ground pad to the vehicle pad.

Wireless charging systems can be employed to wirelessly charge vehicles under varying operating environments or conditions, such as aligned or misaligned parking positions and/or one or more of different vehicle power receiving platforms, air gaps, vehicle metallic bodies, battery voltages, coupling coefficients, or coil inductance values. Some wireless charging systems employ additional hardware to wirelessly charge vehicles under different conditions. For example, some wireless charging systems can include additional hardware to accommodate a relatively wide battery or power supply voltage range (e.g., 200V, 400V, 800V, or the like). The additional hardware may increase cost for building a wireless charging system. Furthermore, achieving efficient wireless power transfer to vehicles may be challenging due to energy loss resulting from toggling or switching of certain power electronics in wireless charging pads. For example, switches of a H bridge circuit in a wireless charging pad may frequently toggle, leading to deadtime loss.

To address at least a portion of the above technical problems, some embodiments of the present disclosure disclose a wireless charging pad capable of charging battery packs under wide voltage ranges by controlling switches of a H bridge circuit to switch among particular configurations. As noted above, rather than periodically toggling each switch of a H bridge circuit when transitioning from one configuration to another configuration, a switch control circuit may control some switches of the H bridge circuit to toggle and control other switches of the H bridge circuit to not toggle.

In some embodiments, the switch control circuit may control a first switch and a second switch arranged in a half-bridge of the H bridge circuit to toggle between open and closed states. The switch control circuit may control a third switch and a fourth switch arranged in the other half-bridge of the H bridge circuit to not toggle. For example, the switch control circuit may control the H bridge circuit to operate in a first switch configuration and a second switch configuration. In the first switch configuration, the first switch is closed, the second switch is open, the third switch is closed, and the fourth switch is open. In transitioning from the first configuration to the second switch configuration, the first switch is open, the second switch is closed, the third switch remains closed, and the fourth switch remains open.

Compared with situations where each of the first switch, the second switch, the third switch, and the fourth switch are controlled to toggle between open and closed states periodically, controlling the H bridge circuit to operate under the first switch configuration and the second switch configuration can result in a lower voltage swing (e.g., 50% reduction) across a resonant tank of a wireless charging pad, thereby allowing the wireless charging pad to charge battery packs under a relatively wide voltage range (e.g., from 200 V to 800 V or from 200 V to 1000 V). More specifically, the lower voltage swing can be due to the resonant tank's ability to maintain a more stable voltage when fewer switches toggle, as opposed to toggling all switches in a switching circuit (e.g., an H bridge circuit). The stability can reduce transient effects and/or energy dissipation. Additionally, fewer switching events associated with toggling between the first switch configuration and the second switch configuration controlled by the switch control circuit may result in less energy loss, such as deadtime loss. In some examples, the disclosed switching techniques (e.g., controlling the H bridge circuit to operate under the first switch configuration and the second switch configuration) can be applicable to capacitive power transfer (e.g., power transfer based on electric field coupling rather than magnetic field coupling).

In some embodiments, the switch control circuit may initially control the H bridge circuit such that each of the first switch, the second switch, the third switch, and the fourth switch periodically toggle between close and open states. Upon detecting one or more conditions, the switch control circuit may control the H bridge circuit to toggle between the first switch configuration and the second switch configuration or among other switch configurations such that some switch remains open or closed when toggling between the other switch configurations. In some embodiments, the one or more conditions may include, but are not limited to, a lighter load interfaced with the H bridge circuit, lower voltage ranges or higher voltage ranges associated with a battery pack to be charged or a power supply. Alternatively or additionally, the one or more conditions can include one or more of battery voltage being within certain ranges (e.g., due to battery packs having different voltage levels or different levels of state of charge of a battery pack), voltage provided to a ground pad being within certain ranges, specified power level being within certain ranges, coupling coefficients associated with the H bridge circuit being within certain ranges, parking inaccuracy being within certain ranges, or measured inductance variations being in certain ranges.

Although the various aspects will be described in accordance with illustrative embodiments and a combination of features, one skilled in the relevant art will appreciate that the examples and combination of features are illustrative in nature and should not necessarily be construed as limiting. More specifically, aspects of the present application may be applicable with various types of vehicle charging mechanisms, power sources, interfaces, and the like. Still further, although a specific H bridge circuit schematic for charging batteries and/or battery packs under different voltage levels will be described, such illustrative H bridge circuit schematic should not necessarily be construed as limiting. Accordingly, one skilled in the relevant art will appreciate that the aspects of the present application are not necessarily limited to application to any particular type of vehicle, vehicle charging infrastructure, communications or illustrative interactions between vehicles, owners/users and wireless battery charging systems.

Generally described, inductive charging, commonly referred to as wireless charging, is a type of wireless power transfer. Inductive charging uses electromagnetic induction to generate, or otherwise provide, electricity to devices without requiring physical electrical connectivity. Specifically, various devices can be placed near a charging station or inductive pad without needing to be precisely aligned or make electrical contact, a physical dock, an electric plug and the like. Such devices include, but are not limited to, vehicles, manufacturing equipment, consumer electronics, medical devices, and the like.

In accordance with aspects of the present application, inductive charging systems are configured to transfer energy through inductive coupling between components. An illustrative charging system includes a transferring component, which may be configured as a charging station or charging pad. A charging pad for wirelessly transferring power to a vehicle can be referred to as a ground pad. An alternating current (e.g., an input current) from a power source passes through an induction coil in the charging station or pad. Based on the input current, the moving electric charge through the induction coil (e.g., a ground pad coil) creates (or elicits) a magnetic field. Illustratively, the strength of the magnetic field may fluctuate, at least in part, on changes or fluctuations in the input electric current's amplitude. The changing magnetic field creates an alternating electric current in an induction coil on a receiving device (e.g., a vehicle pad coil). The induced alternating current in the receiving device can then pass through a rectifier, converting the induced alternating current to a direct current. Finally, the receiving vehicle can include additional charging components and/or systems that utilize the converted direct current to charge battery systems, provide operating power, or a combination thereof.

Greater distances between the ground pad and vehicle pad coils can be achieved when illustrative inductive charging systems use resonant inductive coupling components/techniques. More specifically, in some embodiments, a capacitor can be connected to each induction coil to create two LC circuits with a specific resonance frequency. The frequency of the alternating current is matched with the resonance frequency. Additionally, the matched frequency can be further chosen depending on a typical distance between the sending device and the receiver device with consideration for peak efficiency. Still further, use of other materials for the receiver coil such as silver-plated copper or sometimes aluminum to minimize weight and decrease resistance can be utilized for purposes of energy transfer efficiencies.

is a diagram illustrative of an environmentfor implementing an induction-based wireless charging system in accordance with various aspects of the present application. The environmentillustratively can correspond to commercial implementations, such as parking lots, parking stalls, charging booths, and the like. The environmentcan correspond to private or other non-commercial implementations, such as private residences, etc. By way of an illustrative example, an implementation of an induction-based wireless charging system in a non-commercial implementation can include a ground padthat is configured to generate variable magnetic fields in accordance with an induction charging methodology. As also illustrated in, the ground pad, which can also be referred to as a transmitting component, can correspond to a stand-alone component that may be operable to be mounted or placed on a flooror other planar surface. In some other embodiments, the ground padcan be integrated or combined with other devices or components.

The ground padmay be connected to one or more power sources, such as an input from a utility company, real-time power sources (e.g., solar cells or wind energy sources), stored energy cells, or a combination thereof. The power sources are configured to provide the input alternating current as described herein. The ground padmay be connected via direct electric connectionto the power source, such as via a junction boxlocated on a wall surface.

As illustrated in, in embodiments, the ground padcorresponds to a form factor that allows for the location on the floorfor wirelessly charging with a vehicle having a vehicle pad coil. The ground padmay have a form factor such that the vehicle may be located directly above a top surface of the ground pad. Illustratively, the dimensions of the ground pad(e.g., the height and width of the ground pad) may be configured so that a distance between the top surface of the ground padand a bottom surface of the vehicle meets specific criteria, such as minimum distance between the ground pad coil and vehicle pad coil, maximum distance between the ground pad coil and the vehicle pad coil, and the like. In some embodiments, the vehicle pad and/or ground pad(or combination) may be configured with additional components for adjusting (e.g., statically adjusting and/or dynamically adjusting) such distance or otherwise changing the relative orientation between the ground padand the vehicle.

In some embodiments, the ground padcan be configured to charge a battery pack of a vehicle, wherein the battery pack can have a nominal voltage of over 200 Volts (e.g., a nominal voltage of about 350 Volts or 355 Volts) and a maximum voltage of 400 Volts. In some embodiments, the ground padcan be configured to supply 800 Volts of direct current power. In some embodiments, the ground padcan supply a voltage in a range from about 200 Volts to 1000 Volts, such as a range from about 200 Volts to 800 Volts. The ground padcan wirelessly transfer sufficient power to charge battery packs with such voltages.

illustrates a block diagram of the environmentincluding a wireless charging device(e.g., the ground pad) in wireless communication with a vehicle, such as via induction-based magnetic fields. The wireless charging deviceis further connected to one or more energy sources. Although the wireless charging deviceis illustrated with a direct connection to the energy sources, at least some portion of the input alternating current could be provided via a wireless transmission method. Additionally, in embodiments with multiple power sources, the environment may also include various switching components to cause the selection of energy from individual energy sourcesor a combination of energy sources.

illustrates a block diagram of a ground padthat may function as a wireless charging device(shown in). The ground padcan include at least a ground pad coilfor causing the generation of magnetic fields from an input current provided from an energy source. As illustrated in, the input current can be provided by a direct electric connection.

In some embodiments, the ground padcan also include various sensor componentsA,B,C,D related to the charging process. By way of illustration, the sensor componentsA,B,C,D can be configured for various functions, such as detection of the vehicle, detection of objects, measurement of distances to the vehicle, environmental sensors (e.g., temperature sensors, moisture sensors), pressure sensors, and the like. In an embodiment, the sensor componentsA,B,C,D can include radar sensors. The sensor componentsA,B,C,D can include logic and processing components related to the charging process including operational measurements, operational control, safety measurements, communication components and the like.

Wireless Charging Systems with H Bridge Circuits

illustrate circuit schematic diagrams of example wireless charging systemsA-D. As shown in, each of the wireless charging systemsA-D may include a ground pad (e.g., the ground pad) and a vehicle pad that is attached to or otherwise integrated with a vehicle. For example, the ground pad of the wireless charging systemA may include a capacitorA, a H bridge circuitA, and a resonant tankA as shown in. A vehicle pad of the wireless charging systemA may include a capacitorA, a H bridge circuitA, and a resonant tankA, for example, as shown in. In some embodiments, power may be transferred from a power source (not shown in) through the H bridge circuitA, the resonant tankA, the resonant tankA, and the H bridge circuitA to a battery pack (not shown in) of a vehicle. This power transfer can include wireless power transfer from a coil L1 of the ground pad to a coil L2 of the vehicle pad. Any of the wireless charging systemsA-D can be implemented in accordance with any suitable principles and advantages disclosed herein.

illustrates a circuit schematic diagram of the wireless charging systemA. As shown in, the wireless charging systemA corresponds to an LCC-LCC circuit architecture. As illustrated, the wireless charging systemA includes the capacitorA, the H bridge circuitA, the resonant tankA, the resonant tankA, the H bridge circuitA, and the capacitorA. In an LCC-LCC circuit architecture, an inductor Land capacitors Cand Care coupled between the H bridge circuitA and the ground pad coil Lin the ground pad, and the inductor Land capacitors Cand Care coupled between the H bridge circuitA and the vehicle pad coil Lin the vehicle pad.

illustrates a circuit schematic diagram of the wireless charging systemsB. As shown in, the wireless charging systemB corresponds to a LCC-Series circuit architecture. As illustrated, the wireless charging systemB includes the capacitorB, the H bridge circuitB, the resonant tankB, the resonant tankB, the H bridge circuitB, and the capacitorB. In an LCC-series circuit architecture, an inductor Land capacitors Cand Care coupled between the H bridge circuitA and the ground pad coil Lin the ground pad, and the series capacitor Cis coupled between the H bridge circuitA and the vehicle pad coil Lin the vehicle pad.

illustrates a circuit schematic diagram of the wireless charging systemsC. As shown in, the wireless charging systemC corresponds to a Series-LCC circuit architecture. As illustrated, the wireless charging systemC includes the capacitorC, the H bridge circuitC, the resonant tankC, the resonant tankC, the H bridge circuitC, and the capacitorC. In a series-LCC circuit architecture, series capacitor Cis coupled between the H bridge circuitA and the ground pad coil Lin the ground pad, and the inductor Land capacitors Cand Care coupled between the H bridge circuitA and the vehicle pad coil Lin the vehicle pad.

illustrates a circuit schematic diagram of the wireless charging systemsD. As shown in, the wireless charging systemD corresponds to a Series-Series circuit architecture. As illustrated, the wireless charging systemD includes the capacitorD, the H bridge circuitD, the resonant tankD, the resonant tankD, the H bridge circuitD, and the capacitorD. In a series-series circuit architecture, series capacitor Cis coupled between the H bridge circuitA and the ground pad coil Lin the ground pad, and series capacitor Cis coupled between the H bridge circuitA and the vehicle pad coil Lin the vehicle pad.